1. Technical Field
This invention relates to an eye examination apparatus (device for optometry) and an eye examination method (method for optometry). In particular, this invention relates to such apparatus and method for examining eyes that make it possible to measure optical characteristics when eyesight or contrast sensitivity is measured in the binocular viewing state.
2. Related Art
In measuring eyesight or contrast sensitivity using an eye chart for subjective measurement, the eyes are generally examined one by one. As it has been considered desirable to examine a single eye in a perfectly corrected state, the optical characteristics such as eyesight and contrast sensitivity have been actually measured with the eyesight corrected accordingly. In this regard, the inventors have disclosed an apparatus capable of measuring the contrast sensitivity of a subject eye accurately within a short time by measuring pupil area data on a subject; and an apparatus capable of measuring the optical characteristics with high accuracy by measuring reference light path. (Refer to Patent Documents 1 and 2.)
[Patent Document 1]
JP-A-2003-199712 (paragraphs 0020-0048, FIGS. 1-10)
[Patent Document 2]
JP-A-2001-321340 (paragraphs 0032-0160, FIGS. 1-10)
In measuring eyesight or contrast sensitivity using an eye chart for subjective measurement, it has been considered desirable to examine eyes in a perfectly corrected state and so measurements have been made for one eye at a time. Actually, however, as an object is observed using both eyes, there can be difference in the extent of correction between both eyes in the binocular viewing state.
In this case, there is a possibility of obtaining appropriate eyesight or contrast sensitivity in binocular viewing by making measurements in the binocular viewing state rather than making measurements with both eyes perfectly corrected. The optical characteristics data in such an appropriate binocular viewing state are also important.
An object of this invention is to provide an eye examination apparatus and an eye examination method that make it possible to measure eyesight or contrast sensitivity in the binocular viewing state and further make it possible to measure optical characteristics in such an appropriate binocular viewing state.